Ments



(No Model.)

H. ROBISCHUNG. l MEANS FOR HOLDING-PRINTING PLATES 0N GYLINDRIGAL 0R FLAT 1SURFAGESl tgd Mew 6, 1890.

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UNITED STATES.;

' ATENT OFFICE.

HENRY ROBISCHUNG, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGN- MENTS, TO THE CAMPBELL PRINTING PRESS AND MANUFACTURING COM- PANY, OF NEIV YORK, N. Y.

MEANS FOR HOLDING PRINTING-PLATES ON CYLINDRICAL OR FLAT SURFACES.

SPECIFICATION forming part of Letters Patent No. 427,365, dated May 6, 1890. Application tiled September 23, 1889. Serial No. 324,787. (No modelw) To all whom, it may concern.-

Be it known that I, HENRY RoBIsoHUNG, of Chicago, in the county of Cook and State of Illinois, have invented new and useful Iniprovements in lWIeans for Holding Printing- Plates on Cylindrical or Flat Surfaces, which invention is fully set forth and illustrated in the following specification and accompanying drawings.

The object ofthis invention isto provide an improvement upon means heretofore proposed for securing thin plates of different -lengths upon either cylindrical or flat-form surfaces of the cylinders or beds of printingmachines. A

The invention will iirst be described in detail, and then particularlyT set forth in the claims.

For some kinds of work it is often desirable to print only upon a small part of a sheet or upon a sheet of less size than the maximum upon which the machine is designed to. print, and in such cases it is desirable to avoid using a printing-plate of the maximum length and to be enabled to use short plates for short sheets or short designs.

In the accompanying drawings, VFigure 1 is a vertical longitudinal section through a fiat bed or plate-holder for use upon a reciprocating-bed machine, and Fig. 2 a transverse section through a form-cylinder for a rotary machine, each of said figures showing a thin printing-plate stretched upon them by means which form no part of this invention. Fig. 3 is a transverse section through a form-cylinder, showing a modification by the interposition of a second thin plate between the printing-plate and the cylinder-surface for the purpose of avoiding any deviation 4from a true cylindrical surface being produced in the thin printing-plate by any slight irregularity in the dummy-blocks hereinafter described. l

In said figures the several parts are indicated by reference-numbers, as follows:

The number l indicates the form-cylinder or plate-holder; 2, the thin printing-plate; 3, the permanent grooved block over which one end of a full-length plate is hooked. The

5o straining-levers 4E carry a grooved strip 5, similar to the grooved block 3, over which the straining end of the plate is hooked.

The numbers 6 indicate the strainingscrews, and 7 detachable grooved blocks fitting corresponding grooves 8, formed in the surface of the cylinder or plate-holder, the grooves being of such form as to have an overhanging lip 1l, holding one edge of the grooved plate in place where a plate shorter than maximum length is used. The dummy- 6o blocks 9 are formed to fit the grooves 8, and their tops are flush with and conform exactly to the cylinder or bed-surface.

In Fig. 3 a thin sheet of metal or other suitable substance 1() is interposed between the 65 printing-plate 2 and the surface of the cylinder l to insure a true cylindrical form being given to the printing-plate when stretched over a cylinder, or a true plane surface when stretched over a fiat bedwhere there may be 7c any slight inequality in the dummy-blocks 9.

In this case the grooved -blocks 3 and 7 are made to be as much above the surface of the cylinder or bed l as the surface of the plate 10. As many of the plates lO are used as there are blocks 9, and an additional one for a full-sized printing plate when the end grooved block 3 is in use.

The grooved blocks 7 may be placed in any of the grooves 8, and, as shown, said grooves 8o Aare such in number as will take in each case tion is applicable to a cylinder carrying but one straining-lever 4 and one end grooved block 3, the printing-plate in suoli case covering the entire periphery, except a single gap within which the straining-levers work.

Having thus fully described my said improvements as of my invention I claiml. In a printing-machine, in combination with a form or plate cylinder or bed carrying ree a thin printing plate 0r plates secured by tensional straining over its surface, a detachable grooved block or blocks, as 7, for securing the flxed ends of the plates fitting correspondingly-shaped grooves in said cylinder or bed, and a dummy block or blocks, as 9, fitting said grooves and formed -to be a continuous part of the cylindrical or fiat surface when in place, whereby thin printing-plates of several dimensions may be stretched and firmly held upon a form or plate cylinder or bed, substantially as set forth.

2. In a printing-machine, in combination With a form or plate cylinder or bed carrying a thin printing plate or plates secured thereto by tensional straining over its surface, a detachable grooved block or blocks, as 7, for se- H. RoBIscHUNG.

Witnesses:

A. CRANDALL, A. J. ZWART. 

